Combustion Simulation of Transportation Package Performance in Severe, Long Duration Fire Using Computational Fluid Dynamics Tools

The IAEA regulatory thermal test is designed to bound conditions in historic transportation fire accidents. The regulatory thermal test is a 30 minute, fully engulfing fire at 800°C. The severity of this thermal test is difficult to communicate to the general public, especially in comparison to recent real-world transportation accidents involving long duration fires. This paper describes NWMO’s program to enhance staff skills and modelling techniques in simulating real-world long duration transportation accident fires. The fire modelling and simulation development program is designed to bridge the information gap between the 30 minute regulatory thermal test and real world long duration transportation accident fires.Any established finite element analysis software can model heat transfer boundary conditions to simulate the regulatory thermal test. Modelling the highly dynamic nature of transportation accident fires requires sophisticated computational fluid dynamics analysis tools. Tools such as ANSYS Fluent model the chemical combustion reactions and their interactions with dynamic fluid flow. With Fluent, dynamics of a real-world fire can be modelled and compared to the severity of the regulatory thermal test. NWMO is building an understanding of dynamic nature of hydrocarbon fuel fires and their transient effects on large transportation packages by simulating the interaction between combustion and dynamic fluid flow.